Unemployment is low, inflation is historically low and even wages are perking up, leading many observers to believe the U.S. economy is humming along nicely. So why do many Americans say they are struggling?

A new book born of meticulous, years-long research offers a fresh insight into this burning question. Month-to-month swings in income, even for those with full-time jobs, are often the cause of Americans” financial anxiety, claim the authors of “The Financial Diaries: How Americans Cope in a World of Uncertainty.”

For a stunning number of American households, both income and expenses swing 25% or more in either direction on a regular basis, leaving many families scrambling on a month-to-month basis, even if things don’t look so bad annually, the authors argue in their book and a Harvard Business Reviews essay.

Economic data tends to examine broad movements; even at its most micro, it tends to identify years-long trends. Researchers Jonathan Morduch and Rachel Schneider had a sense government statistics were missing things, so they went nano. They spent 12 months getting 235 families to track every single dollar going in and out — 300,000 cash flow events in all. The product of their painstaking research offers perhaps the clearest view yet of why even middle-class Americans find themselves living with deep economic anxiety. The book even offers up a new term — “precarity,” or precarious economic volatility — to describe the plight of everyday Americans.

One of the more bold claims made in the book: Despite all the talk about income inequality, the authors say income instability has risen even faster and is the more immediate problem.

Lexington Law Credit Repair:

Need Credit Repair Help?

Lexington Law can help you remove negative items on your credit reports

What’s Income Instability?

Many readers are familiar with the idea that unexpected expenses — like a health scare or major auto repair bill — can derail many households. But the book establishes another reality that might be new to many: income volatility, even among those with full-time jobs.

The book’s opening anecdote cites a research subject who works as a truck mechanic in Ohio. While he works full time, his pay relies largely on commissions and can vary from $1,800 to $3,400 each month. In bad weather, trucks break down more often. That means in the spring and fall months, mortgage payments aren’t made, and the electricity bill goes unpaid. Later, for a fee, the family catches up. (You can see how any missed loan payments may be affecting your credit scores by viewing your free credit report summary on Credit.com.)

This same problem is repeated again and again among the families studied. Morduch and Schneider found that the term “average income” is a bit of a farce, as typical families lived through five months each year with income that swings either 25% above or below “average.”

“This is creating a lot of anxiety and uncertainty that is impossible to see in the usual data,” Morduch said in an interview. About five months out of each year, incomes “weren’t even close” to average.

“Often we see the (financial) problems as a discipline problem, a failure of personal responsibility. What we’re trying to say is there’s something else going on,” he said. “The underlying conditions are really hard. It probably isn’t just about self-discipline.”

Income swings are to be expected among families suffering job loss, the self-employed or those who rely on tips, like waiters. But the researchers found a stunning rate of income volatility even among those with traditional-sounding full-time jobs.

“This was the single biggest surprise (in the research),” Morduch said. “There’s insecurity that’s because you are going to lose your job, but that’s not what’s driving anxiety for these folks … What we see is that when paychecks bounce from month to month, people can be making good financial choices but are still struggling.”

As a result, even earners who are safely in the middle class spent a month or two living as poor or “near poor,” the book says. The problem for many is better described as a lack of liquidity — getting enough cash to pay the mortgage this month — than as insolvency, or a hopeless difference between income and expenses.

“Not balancing on a high wire, driving on a rocky road,” the book says. “(There’s a) distinction between not having money at the right time vs. never having the money.”

While economists might just be becoming aware of this month-to-month struggle, the financial industry has known about it for some time. That’s one reason there are more payday lending storefronts in America than McDonald’s restaurants. (You can find tips for escaping payday loan debt here.)

Trouble Saving for a Rainy Day

The volatility problem is closely related to Americans’ lack of emergency savings. Study after study shows a large percentage of Americans don’t have the recommended three months of living expenses stored in short-term savings. Some studies show even more dire data. A stunning 46% of Americans told the Federal Reserve in 2015 they could not cover an emergency $400 expense without selling something or borrowing the money. Income and expense volatility, combined with no savings, is a perilous combination.

“Households don’t have a big cushion. Into this mix is the reality that levels of income have not risen – the bottom 50% has seen no income growth since 1980 — then you are really squeezed,” said Morduch. As a result, even in good months, earners don’t have any extra left over to build a rainy-day fund – economists say their budgets have no “slack.”

“There is a knock-on effect of diminished slack so when the budget gets hit by a car repair or the house needs a new roof, it’s just that much harder,” Murdoch said.

How did this income volatility come to pass? The authors blame what they call “the Great Job Shift.” Employers are increasingly sharing risk with their workers. That means cutting back hours, often on the spot, when times are slow. Or basing a large portion of pay on commission, as in the case of the truck mechanic. In other cases, workers rely on tipping to top-up wages that otherwise aren’t livable. In one of the book’s more frustrating scenes, as casino blackjack dealer in Mississippi describes how her income relies on events as whimsical as the nearby college football team schedule.

The subjects in the book are anonymized. Their names changes and a few other personally identifiable data points have been obscured, but otherwise, their financial diaries are disturbingly real.

How Do We Fix it?

When asked for policy recommendations, Morduch leaps to the defense of the Consumer Financial Protection Bureau, which he says is working hard to regulate many of the short-term lending products that have emerged to services workers with volatile incomes. He says there’s also been constructive conversations with large firms about making hourly wage worker schedules more predictable, and moving away from so-called on-call workers. The “Schedules That Work Act” that would have promised some workers two-weeks scheduling notices was considered but tabled by Congress under President Barack Obama.

Other changes would help, too. Many social benefits programs are cumbersome to apply for and don’t offer much help for families who are only occasionally “near poor,” and might need help one or two months per year.

Changes that could encourage saving for short-term events would help, too. Tax-advantaged products like 401K accounts help families plan for decades in the future, but families living on the margins are afraid to use them for emergency savings because of the severe early withdrawal penalties. (You can learn more about withdrawing from your 401K here.) More flexible rules would encourage greater use of retirement accounts, Morduch believes.

Sign up for our weekly newsletter.

Sign up for our Credit Report Card and receive the latest tips & advice from our team of 50+ credit and money experts as well as a FREE Credit Score and action plan. Sign up now.

Bob Sullivan is author of the New York Times best-sellers Gotcha Capitalism and Stop Getting Ripped Off. His stories have appeared in The New York Times, the Wall Street Journal, and hundreds of other publications. He has appeared as a consumer advocate and technology expert numerous times on NBC's TODAY show, NBC Nightly News, CNBC, NPR's Marketplace, Terry Gross' Fresh Air, and various other radio and TV outlets. He helped start MSNBC.com and wrote there for nearly 20 years, most of it penning the consumer advocacy column The Red Tape Chronicles. See more at www.bobsullivan.net. Follow Bob Sullivan on Facebook or Twitter. More by Bob Sullivan

Comments on articles and responses to those comments are not provided or commissioned by a bank advertiser. Responses have not been reviewed, approved or otherwise endorsed by a bank advertiser. It is not a bank advertiser's responsibility to ensure all posts and/or questions are answered.

Please note that our comments are moderated, so it may take a little time before you see them on the page. Thanks for your patience.

Certain credit cards and other financial products mentioned in this and other sponsored content on Credit.com are Partners with Credit.com. Credit.com receives compensation if our users apply for and ultimately sign up for any financial products or cards offered.

Hello, Reader!

Thanks for checking out Credit.com. We hope you find the site and the journalism we produce useful. We wanted to take some time to tell you a bit about ourselves.

Our People

The Credit.com editorial team is staffed by a team of editors and reporters, each with many years of financial reporting experience. We’ve worked for places like the New York Times, American Banker, Frontline, TheStreet.com, Business Insider, ABC News, NBC News, CNBC and many others. We also employ a few freelancers and more than 50 contributors (these are typically subject matter experts from the worlds of finance, academia, politics, business and elsewhere).

Our Reporting

We take great pains to ensure that the articles, video and graphics you see on Credit.com are thoroughly reported and fact-checked. Each story is read by two separate editors, and we adhere to the highest editorial standards. We’re not perfect, however, and if you see something that you think is wrong, please email us at editorial team [at] credit [dot] com,

The Credit.com editorial team is committed to providing our readers and viewers with sound, well-reported and understandable information designed to inform and empower. We won’t tell you what to do. We will, however, do our best to explain the consequences of various actions, thereby arming you with the information you need to make decisions that are in your best interests. We also write about things relating to money and finance we think are interesting and want to share.

In addition to appearing on Credit.com, our articles are syndicated to dozens of other news sites. We have more than 100 partners, including MSN, ABC News, CBS News, Yahoo, Marketwatch, Scripps, Money Magazine and many others. This network operates similarly to the Associated Press or Reuters, except we focus almost exclusively on issues relating to personal finance. These are not advertorial or paid placements, rather we provide these articles to our partners in most cases for free. These relationships create more awareness of Credit.com in general and they result in more traffic to us as well.

Our Business Model

Credit.com’s journalism is largely supported by an e-commerce business model. Rather than rely on revenue from display ad impressions, Credit.com maintains a financial marketplace separate from its editorial pages. When someone navigates to those pages, and applies for a credit card, for example, Credit.com will get paid what is essentially a finder’s fee if that person ends up getting the card. That doesn’t mean, however, that our editorial decisions are informed by the products available in our marketplace. The editorial team chooses what to write about and how to write about it independently of the decisions and priorities of the business side of the company. In fact, we maintain a strict and important firewall between the editorial and business departments. Our mission as journalists is to serve the reader, not the advertiser. In that sense, we are no different from any other news organization that is supported by ad revenue.

Visitors to Credit.com are also able to register for a free Credit.com account, which gives them access to a tool called The Credit Report Card. This tool provides users with two free credit scores and a breakdown of the information in their Experian credit report, updated twice monthly. Again, this tool is entirely free, and we mention that frequently in our articles, because we think that it’s a good thing for users to have access to data like this. Separate from its educational value, there is also a business angle to the Credit Report Card. Registered users can be matched with products and services for which they are most likely to qualify. In other words, if you register and you find that your credit is less than stellar, Credit.com won’t recommend a high-end platinum credit card that requires an excellent credit score You’d likely get rejected, and that’s no good for you or Credit.com. You’d be no closer to getting a product you need, there’d be a wasted inquiry on your credit report, and Credit.com wouldn’t get paid. These are essentially what are commonly referred to as "targeted ads" in the world of the Internet. Despite all of this, however, even if you never apply for any product, the Credit Report Card will remain free, and none of this will impact how the editorial team reports on credit and credit scores.

Your Stories

Lastly, much of what we do is informed by our own experiences as well as the experiences of our readers. We want to tell your stories if you’re interested in sharing them. Please email us at story ideas [at] credit [dot] com with ideas or visit us on Facebook or Twitter.